Multiple underfeed stoker



Feb. 4, 1936. B. F. HARRISON MULTIPLE UNDERFEED STOKER 6 Sheet s-Sheet 1 Original Filed Nov. 5, 1931 INVENTIOR ery'amzzzFi/mw- 1022 B BY A TTORNEY B. F. HARRISON 2,029,296

' MULTIPLE v UNDERFEED STOKER Original Filed Nov. 5, 1931 6 Sheets-Sheet 2 Feb. 4, 1936.

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A TTORNE Y Feb. 4, 1936. B. F. HARRISON MULTIPLE UNDERFEED STOKER Original Filed Nov. 5, 1931 6 Sheets-Sheet I5 am V i 7 i mmvroge Benjamin V/draw]? BY a; ATTORNEY Feb. 4, 1936. B. F. HARRISON MULTIPLE UNDERFEED STOKER 5, 1931 6 Sheets-Sheet 4 Original Filed Nov.

ATTORNEY Fab. 4, 1936. B. F. HARRISON MULTIPLE UNDERFEED STOKER Original Filed Nov. 5, 1931 6 Sheets-Sheet 5 570K156 ENG/NE IN VEN TOR ga 2222M? P my/1012 (a, ATTORNEY Feb. 4, 1936. B. F. HARRISON MULTIPLE UNDERFEED STQKER Original Filed Nov. 5, 1931 6 Sheets-Sheet 6 INVENJTOR amzizFi/Maazz f A TTORNEY Patented Feb. 4, 1936 MULTIPLE UNDEBFEED STOKER Benjamin F. Harrison, Glenns Ferry, Idaho, assignor to The Standard Stoker Company, Incorporated, a corporation of Delaware Application November 5, 1931, Serial No. 573,069 Renewed July 11, 1935 11 Claims.

The present method of inducing draft for the locomotive is by the use of the ordinary exhaust nozzle. This method of drafting the locomotive has the advantage that the draft intensity varies automatically with the load imposed upon the engine. Its greater disadvantage, which has long been recognized, arises from the back pressure which the restricted discharge area imposes on the cylinders, and which entails, under certain conditions of service, a serious decrease in cylinder output.

To overcome this disadvantage many attempts have been made to produce the draft by mechanical means in order to eliminate the exhaust nozzle. Until very lately, all such devices consisted of a turbine driven fan located in the 'front end on the smoke box of the locomotive and, like the standard exhaust nozzle, they all produced what is known as induced draft. These induced draft devices, located in the front end, have all two major dificulties. In the first place, the fan working in a restricted space, had to be designed to handle an enormous volume of hot gas, and in the second place, it has been difficult to maintain the machinery in the current of hot gas and against the abrasive action of the hot cinders.

In use with switching locomotives or other types wherein the throttle is opened and closed at short intervals, the exhaust nozzle presents certain .difficulties. throttle does not supplythe proper amount of air at the proper time and in a uniform manner. It is almost impossible to maintain a fire that will withstand the extremes imposed upon it by working an open throttle for a short time, only to be shut off abruptly leaving the fire with no supply of air except what may be furnished by the use of the blower.

With the use of forced draft it-is necessary that the firebox be substantially air tight at all times. This precludes manual firing of forced draft locomotives and leaves the mechanical stoker as the alternative. The use of forceddraft on locomotives has been retarded to a certain extent due to the fact that existing forms of stokers are not entirely adaptable to a forced draft locomotive. It is the main object of this invention to provide a stoker for locomotivesof the forced draft type which may be applicable to existing power.

Another object of this invention is the provi sion of a stoker having a multiple feed feature which permits the stoker to be designed to meet the requirementsof any conventional locomotive boiler.

The irregular use of the.

A further object of the invention is the provision of a stoker for locomotives .of' the forced draft type wherein the proper mixture of oxygen with the fuel is effected at the discharge opening of the stoker.

A still further object of this invention is the provision of a novel stoker arranged to feed fuel from beneath the firebed and having its parts so organized as to occupy a minimum amount of space in the tender.

It is also an object of this invention to provide a stoker having a novel crushing, driving and conveying mechanism.

Other and further objects and advantages of this invention will appear from the following description when read in connection with the accompanying drawings, in which Fig. 1 is a central longitudinal section of a locomotive and its tender embodying the preferred form of this invention;

Fig. 2 is a plan view taken on the line 2-2 of Fig. l; v

Fig. 3 is an enlarged view of the tender unit flexible supporting means;

Fig. 4 is a sectional-view on the Fig. 5 is a section on the line 5--5 of Fig.1;

Fig. 6 is a central longitudinal section through a portion of the locomotive showing a st'oker' somewhat modified from the form shown'in Fig. 1;. 30

Fig. 7 is a section on the line 1-1 ofjFigj 6;

Fig. 8 is a section on the line 88 of Fig.6 showing the driving arrangement;

Fig. 9 is a section on the line 99'of Fig. 2;

Fig. 10 is a sectional view taken on the line Ill-l of Fig.9; U

Fig. 11 is a partial section of a locomotive showing the firedoor structure used in connection with this invention; V

Fig. 12 is an elevation of the backhead of the locomotive; and

Fig. 13 is a partial longitudinal view of 2.1000- motive equipped with a forced draft arrangement of a slightly different design than that shown in the other forms of this invention."

Referring now to the drawings and inparticular to Figs.- 1 to inclusive, the locomotive is designated at Ill having the usual boiler ll enclosing the firebox l2. The tender for the locomotive is shown at l3 having a fuel bin It and a water compartment IS, The frame l6 of the locomotive and the base portion l'l on which the tender rests are coupled as at l8.

Means for feeding fuel to the firebox I2 is provided, which means includes a transferrlngcon- 55 li er-'4 of' veyor A mounted on the frame l6 of the locomotive l0 and a transferring conveyor B for conveying fuel from the fuel bin I4 of the tender to the conveyorA on the locomotive. The transferring conveyor A comprises a hopper l9 having a tubular extension 28 to which may be secured any suitable number of casings such as 2|, 22, and '23, which extend beneath the firebox |2. The casings 2|, 22, and 23 are each provided with the discharge throat 24 formed by the inclined walls 25. Tuyere members. 26 whose inner walls are a continuation of the inclined walls of the discharge throat 24 are seated on the flange portions 21 of said discharge throat.

Screw means are employed to convey fuel through the conveyor A and through the discharge throat 24 of each of the casings 2|, 22, and 23. In order that an equal amount of fuel may be delivered through each of the discharge sign to meet such a requirement by a progressive reduction of the screw diameter in its respective casing. vThe screw conveyor 28 is shown as being preferably formed of short sections which are coupled to each other in any suitable manner. It could also be made as an integral casting but for the purpose of repairs and also to provide for a varying number of casings 2|, 22, and 23, the screw conveyor is shown as being sectional.

Located beneath the floor 29 of the fuel bin I4 and in communication with the opening 30 therethrough is a mouth portion 3| of the transferring conveyor B. A tubular extension 32 extends forwardly and downwardly from said mouth portion 3| and has its discharge opening 33 in communication with the hopper H). A conveyor screw 34 within the transferring conveyor B receives the fuel from the bin l4 through the open, ing 38 and carries it forwardly through they tubular extension 32 and into the hopper l9. Suitable crushing means 35 is interposed between the discharge opening 33 of the transferring conveyor B and the hopper IQ of the sectional conduit A as will hereinafter be described in more detail.

Means for driving the screws 28 and 34 and the crushing means 35 comprise a motor 36 best shown in Figs. 1 and 2 which imparts rotary motion to a gear 31. A gear 38 mounted on the shaft 33 of the screw conveyor 28 meshes with the gear 31 thereby imparting motion to said screw. Likewise, a. gear 46 mounted on the shaft 4| on which is mounted a roll crusher 42, engages the gear 31.' The roll crusher 42 engages the larger lumps of coal between the lip members 43 of the hopper l9 and reduces them to a size suitable for efiicient firing. 0n the opposite end of the shaft 4| is mounted a gear 44 which cooperates with the gear 45 to drive the conveyor screw 34.

In order to provide for the necessary articulation between the transferring conveyor A and the transferring conveyor B mounted on the locomotive and tender respectively, the transferring conveyor 13 is suspended from the floor 29 of the fuel bin I4 by a bolt 46. A spherical section 41 of the bolt 46 seats in a complementary section .48 rnounted on the floor 29 and a slot 49 is provided in the flange member 58 of the transferring conveyor 13. The bolt 46 passes through the slot4 9' ofthe flange member 56 and a nut 5| provides a rest for the bottom of the flange.

The forward end of the conveyor screw 34 is connected to the gear 45 by a universal joint 52,

and extending outwardly from the tubular extension 32 are the rollers 53 which rest on the table like portion 54 of the hopper l9. The rollers 53 are utilized to firmly support the transferring conveyor B and still provide flexibility to insure safety to all parts of the stoker when the locomotive and tender are rounding curves. It is apparent. to those familiar with the locomotive stoker art that the necessary provision for articulation of the locomotive and tender units of this device have been adequately met.

, While thestoker herein described is applicable to all modern locomotives, it is the particular aim of this invention to provide a stoker for switching locomotives where the tender capacities are small. It will be noted from the drawings that the mouth portion 3| only of the transferring conveyor B is wholly within the alcove 55. The alcove 55 is formed by the floor 29, the end plate member 56 and the side plate members 51, as best shown in Figs. 1, 2, and 4. The rear slope sheet 58 and the side slope sheets 58a, of the fuel bin l4 are sloped downwardly to the outer margin of the opening 36 and cooperate to form the fuel bin which is of a substantially self cleaning type.

Preferably, though not necessarily, this stoker is particularly adaptable to a locomotive of the forced draft type. In this type it is necessary that the firebox of the locomotive be made as nearly air tight as possible. The usual method of forming the .firebox as an air tight chamber is by making the ash pan fit snugly against the mudring of the boiler and by providing a firedoor which would not be apt to blow open when the forced draft arrangement is in operation. All locomotives that employ solid fuel as a source of heat for the boiler must necessarily be equipped with an ashpan. The particular construction of the ashpan used in my device forms no partof my invention and may be of a conventional type which will form with the firebox a substantially air tight chamber. The ashpan has not been illustrated in the drawings since it is not essential to a complete understanding of the invention.

Located at one side of the locomotive rearwardly of the firebox is a variable speed turbine driven fan 59 which is employed to create the necessary draft for the locomotive. An air duct 60 in communication with the fan 59 is located beneath the firebox l2 and is arranged to discharge a blast of air to the tuyeres 26. Referring to Figs. 2, 9, and 10; at 6| is shown a substantially V-shaped channel leading from the passage 62 of the tuyere 23 to the air duct 68. Gates 63, 63a arranged to open or close the opening 64 provide an independent control of the amount of air supplied toeach tuyere. A nut 65 on the threaded stem 66 is engaged by the pins 61, 61a of the gates 63, 63a respectively. As the threaded stem is rotated by the handwheel 68 the nut 65 will be caused to move upwardly or downwardly, depending upon the direction in which the handwheel 68 is rotated, and thereby either opening or closing the gates 63, 63a.

The draft created by the fan 59 passes through the air duct 66, thence by way of the opening 64 it is diverted through the V-shaped channels 6| to the passages 62 of the tuyeres 26. The inner walls of the tuyeres are slotted as at 69 and in this manner the coal receives a proper amount of air as it rises upwardly through the tuyres 26 and then is spread over the table grates 16.

On Figs. 11 and 12, there are shown some features of this invention which are deemed necessary to a locomotive of the forced draft type. A specially constructed firedoor II is provided for the opening 12 in the boiler The firedoor comprises a frame I3 and a hinged cover ll therefor. Secured to the inner face of the hinged cover N is a perforated plate I5. In order that the parts of the flredoor that are exposed to the heat may be protected, a pipe 16 is used to bypass a portion of the draft created by the fan 59 to the rear of the perforated plate I through the passage 11. The cover I4 is securely held in a closed position by the latch 18. While the element 1| has been referred to as a firedoor, this is not so in the true sense of the word, as the socal'led firedoor is never opened while the forced draft arrangement is in operation. Ferrules passed through the boiler II and the firedoor 1| are covered with mica windows 19 so that an inspection of fire conditions within the firebox may be made without opening the firedoor.

Steam is conducted from the locomotive turret 89 by means of the main steam pipe 8| and then through branch pipes to supply the blower, fan turbine and the stoker engine as shown in Fig. 12.

Locomotive fireboxes vary in length and width according to the physical characteristics of the road, the grade of fuel used and the heat requirements of the boiler. In order to meet the requirements of the different sized and shaped fireboxes in general use, the number and arrangement of the feeding devices must be capable of variation. Thus the preferred form of my invention shown in Figs. 1 and 2, may be modified to meet the requirements of a longer firebox by adding an additional casing to the casings 2|, 22, and 23 and providing it with a similar feeding device. In Figs. 6, 7, and 8, is illustrated a modification particularly adaptable to wide fireboxes but it will be evident that it may be used equally as well with other fireboxes. This modification provides a plurality of feeding devices extending the width of the firebox as well as the length of the firebox and is hereinafter described more in detail.

The plurality of transferring conveyors C, C comprise a common hopper 8| having the tubular extensions 82, 82a to which may be secured in any suitable manner the casings such as 83 and 84. Sectional screw conveyors 85, 860. within the conveyors C, C, are employed to discharge the fuel through the tuyeres 26a in a manner as hereinbefore described in connection with the preferred form of this invention. Fuel is conveyed from the tender by the screw 34.

within the conduit B.

V In operation, coal falls by gravity from the fuel bin l4 through the opening 30' of the floor 29 and into the mouth portion 3| of the transferring conduit B. The screw conveyor 34, therein urges the fuel forwardly and it is discharged through the opening 33. At this point the larger lumps of coal are engaged by the roll crusher 42 and after reduction to proper size drop into the hopper i9. The sectional screw 28 therein receives the fuel and conveys it forwardly to the casings 2|, 22, and 23, and then it is raised by the action of this screw through the discharge throat 24 in each of the casings and through the tuyeres 2'5 thereon.

A proper amount of air necessary for emcient combustion of the fuel is provided by the forced draft arrangement. As stated before, the turbine driven fan 59 creates the draft which is conducted through the air duct 60 then by way of the opening H which is controlled by the gates 63, No it passes through the channels 6| to the passage 62 of the tuyere 25 where the air mixes with the column of fuel issuing therethrough.

The motor 36 drives the gear shaft 81 on which are mounted several gears. The gears 88, 89a engage the gears 89. 99a, of the sectional screw conveyors 86, 86a respectively, and impart motion thereto. The gear 90 on the shaft 91 meshes with the gear 9| on the counter shaft 92. A gear 93 mounted on the opposite end of the counter shaft 92 cooperates with the gear 94 to drive the screw 34 within the transferring conveyor B.

Above the sectional screws 8'5, 86a are the roll crushers 95, 95a mounted on the shafts 96, 96a respectively. Gears 91, 91a mounted on the shafts 96, 96a are driven by the gears 98, 98a respectively-of the gear shaft 81. The roll crushers 95, 95a. engage the larger lumps of coal between the sidewalls 99, 99a of the hopper 8| and reduce them to a size suitable for firing.

The forced draft arrangement has not been treated in this modification of the preferred form but it is apparent that the draft arrangement shown in the preferred form of this invention is readily applicable in this and other instances and a repeated description thereof is here omitted.

In operation, this form of stoker is similar to the preferred form with the exception that the fuel as delivered by the screw 34 from the fuel bin I4 is divided into a plurality of streams, re-

duced to a proper size by the roll crushers 95, 95a then the fuel is received by the sectional screw conveyors 86, 8611. within the conveyors C, C. The sectional screw conveyors 86, 86a discharge the coal through the tuyres 26a in a manner in which the sectional screw 28 of the conduit A discharges the coal through the tuyeres 26 of the preferred form. Forced draft is supplied to the tuyeres by the turbine driven fan 59 similar to the manner shown in Figs. 2, 9, and of the preferred form of this invention and for this reason further explanation is deemed unnecessary.

Figure 13 shows a portion of a locomotive with an underfeed stoker having forced draft arrangement somewhat different from that shown in the other drawings. This arrangement consists in relocating the turbine driven fan I24 whenever the deck I25 of the locomotive is located so as to preclude the application of this fan beneath said deck.

From the foregoing it will be observed that a stoker has been provided which meets the fundamental principles of combustion by furnishing a supply of fuel from beneath the fire and by providing a draft arrangement which is capable of supplying the proper-amount of air at all times to the fire.

This is a continuation in part of my application Serial No. 369,829, filed June 10, 1929.

I claim:

1. In combination with a locomotive having a a firebox and tender provided with a fuel bin. a stoker for conveying fuel from said bin to said firebox including fuel transferring means havinga gear drive at its forward end on the locomotive, fuel transferring means communicating with and extending forwardly from said first named transferring means and having a gear drive mounted at its rearward end on said 1000- motive, a gear shaft interposed between the gear drives of the respective transferring means, means on one end of said gear shaft operatively connecting it with the gear of one of said conveyors, a power shaft operatively connected to said gear shaft and with the gear of the other of said conveyors, and a fuel crushing means mounted on said interposed shaft for crushing the larger lumps of fuel as they are delivered from the first named to the second named transferring means.

2. In combination with a locomotive having a firebox and tender provided with afuel bin,

. a stoker for conveying fuel from said bin to said firebox including a fuel transferring conveyor having a gear drive at its forward end on the locomotive, a plurality of fuel transferring conveyors communicating with and extending forwardly from beneath said first named conveyor and having gear drives mounted at their rearward ends on said locomotive, a drive shaft and a plurality of shafts having crushing means mounted thereon interposed between the gear drive of said first named conveyor and the gear drives of said plurality of conveyors, said drive shaft being provided with gears for transmitting motion to said first named conveyor, and a second drive shaft provided with gears transmitting motion to said interposed drive shaft. crusher shafts and said plurality of conveyors,

3. In combination with a locomotive having a firebox and tender provided with a fuel bin, a stoker for conveying fuel from said bin to said firebox including a conduit mounted at its rearward end on the tender and atits forward end on the locomotive, a second conduit mounted on the locomotive and communicating with said first named conduit, means in said first named conduit for advancing fuel from the tender to the conduit on the locomotive, means in the second named conduit for advancing the fuel toward the .firebox, and fuel crushing means on the locomot've interposed between said first named conduit and said second named conduit at their point of communication.

4. In combination with a locomotive, having a firebox, and a tender, a stoker including a conduit mounted at its rearward end on the tender and at its forward end on the locomotive, a second conduit mounted on the locomotive communicating with and extending forwardly from beneath said first named conduit beneath said firebox, said second named conduit being composed of sections progressively diminishing in diameter from the rearward to the forward section, a plurality of discharge outlets at the top of said second named conduit opening into said firebox, a tuyre surrounding each of said discharge outlets, a screw in said first named concluitand a screw in each of the sections of said second named conduit for advancing fuel therethrough and delivering it to the firebox through said discharge openings.

5. In combination with a locomotive having a firebox and a tender provided with a fuel bin, a stoker including a conduit extending from beneath said fuel bin to said locomotive, a second conduit mounted on the locomotive communifirebox and tender, the latter having a fuel bin provided with a fioor, a stoker for conveying fuel from said bin to said'firebox including a conduit swivelly supported at its rearward end from said floor immediately beneath said fuel bin and slidably mounted at its forward end on the 1000- motive, a second conduit rigidly mounted on the locomotive and communicating at its rearward end with the forward end of said first named conduit, means in each of said conduits for advancing fuel therethrough and fuel crushing means interposed between the communicating, ends of said conduits.

7. In combination with a locomotive having a firebox and a cab deck and .a tender provided with a .fuel and a water compartment and a tender deck, an alcove in said water compartment beneath and communicating with-said fuel compartment, a stoker for conveying fuel from said fuel compartment to said fireboxincluding a fuel transferring conveyor swivelly mounted at its rearward end in said alcove andarranged to receive fuel from said fuel compartment and slidably mounted at its forward end on said locomotive, said transferring conveyor extending downwardly and forwardly from said alcove beneath the tender and cab deck.

8. In combination with a locomotive having a firebox, and a tender, a stoker including a conduit mounted at its rearward end on the tender 1 and at its forwardend on the locomotive, a second conduit mounted on the locomotive communicating with and extending forwardly from beneath said first'named conduit to a point beneath said firebox, said second named conduit being composed of sections progressively diminishing in diameter from the rearward to the forward section, a plurality of discharge outlets at the top of said second named conduit opening into said firebox, a tuyre surrounding each of said discharge outlets, a blower for introducing air under pressure to each of said tuyeres, means for controlling the flow of air into each of said tuyeres independently, a conveyor screw in said first named conduit, and a conveyor screw in each of the sections of said second named conduit for advancing fuel therethrough and delivering it to the firebox through said discharge outlets.

9. In combination with a locomotive having I.

a firebox and tender provided with a fuel bin, a stoker for conveying fuel from said bin to said firebox including fuel transferring means having a gear operatively connected to its forward end, fuel transferring means communicating with and extending forwardly from said first named transferring means and having a gear operatively connected to its rearward end, a gear shaft interposed between the gears of the respective transferring means, means on one end of said gear shaft operatively connecting it with the gear of one of said conveyors, a power shaft operatively connected with said gear shaft and to the gear of the other of said conveyors, and

a fuel crushing means mounted on said interposed shaft for crushing the larger lumps of fuel as they are delivered from the first named to the second named transferring means.

10. In combination with a locomotive having a firebox and tender provided with a fuel bin, a stoker for conveying fuel from said bin to said firebox including a fuel transferring conveyor having a gear drive at its forward end, a plurality of fuel transferring conveyors communicating with and extending forwardly from be neath said first named conveyor and having gear drives mounted at their rearward ends, a, drive shaft and a plurality of shafts having crushing means mounted thereon interposed between the gear drive of said first named conveyor and the gear drives of said plurality of conveyors, said drive shaft transmitting motion to said first named conveyor, and a second drive shaft transmitting motion to said interposed drive shaft, crusher shafts and said plurality of conveyors.

11. In combination with a locomotive having a firebox and a tender provided with a fuel bin, a stoker for conveying fuel from said bin to said firebox comprising fuel transferring means receiving fuel from said fuel bin, said transferring means including a conveyor having a gear opernected with said gear shaft and to the gear of the other of said conveyors.

BENJ. F. HARRISON. 

